Electric field application for single shot cardiac ablation by irreversible electroporation

Abstract

Disclosed herein are apparatus, systems, and methods for ablating tissue in a patient by electroporation. Embodiments generally include an ablation catheter having a hand, a shaft, and an electroporation electrode arrangement. The shaft has a distal end and defines a longitudinal axis of the ablation catheter. The electroporation electrode arrangement is at the distal end of the shaft and is configured to generate a multidirectional electric field when at least one pulse sequence is delivered thereto. The multidirectional electric field includes at least two of the following directions relative to the longitudinal axis: generally axial, circumferential, and transverse. The electroporation electrode arrangement is configured to operatively couple to an electroporation generator that is configured to generate the at least one pulse sequence and is configured to receive the at least one pulse sequence from the electroporation generator.

We claim: 
     
         1 . An electroporation ablation system for treating target tissue, the electroporation ablation system comprising:
 an ablation catheter including:
 a handle; 
 a shaft having a distal end and defining a longitudinal axis of the ablation catheter; and 
 an electroporation electrode arrangement at the distal end of the shaft and including a plurality of electrodes spatially arranged so as generate a plurality of electric fields when an electrical pulse sequence is delivered to selected pairs of the electrodes, the plurality of electric fields including a first electric field having a first orientation relative to the longitudinal axis, and second electric field having a second orientation relative to the longitudinal axis; and 
   an electroporation generator operatively coupled to the electroporation electrode arrangement and configured to selectively generate and deliver the electrical pulse sequences to each selected pair of electrodes.   
     
     
         2 . The electroporation ablation system of  claim 1 , wherein the first orientation is generally aligned with the longitudinal axis, and wherein the second orientation is circumferential about the longitudinal axis. 
     
     
         3 . The electroporation ablation system of  claim 1 , wherein the first orientation is generally aligned with the longitudinal axis, and wherein the second orientation is transverse to the longitudinal axis. 
     
     
         4 . The electroporation ablation system of  claim 1 , wherein the first orientation is transverse to the longitudinal axis, and the second orientation is generally circumferential about the longitudinal axis. 
     
     
         5 . The electroporation ablation system of  claim 1 , wherein each of the plurality of electrical pulse sequences comprises a plurality of direct current (DC) pulses. 
     
     
         6 . The electroporation ablation system of  claim 5 , wherein the DC pulses are monophasic pulses, biphasic pulses, or triphasic pulses. 
     
     
         7 . The electroporation ablation system of  claim 5 , wherein the electroporation generator is configured to generate the DC pulses of each pulse sequence separated by an inter-pulse delay, and wherein at least some of the DC pulses of a first electrical pulse sequence are delivered during a respective inter-pulse delay of a second electrical pulse sequence. 
     
     
         8 . The electroporation system of  claim 1 , wherein the electroporation generator is configured to generate a plurality of electrical pulse sequence sets having a pause therebetween, wherein each electrical pulse sequence set comprises a plurality of electrical pulse sequences. 
     
     
         9 . The electroporation ablation system of  claim 5 , wherein the electroporation generator is configured to generate the DC pulses of each electrical pulse sequence separated by an inter-pulse delay, and wherein at least some of the DC pulses of the second electrical pulse sequence are delivered during a respective inter-pulse delay of the first electrical pulse sequence. 
     
     
         10 . The electroporation ablation system of  claim 5 , wherein DC pulses are biphasic pulses, and the electroporation ablation generator is configured to alternate between delivering the first electrical pulse sequence to the first anode-cathode pair, and the second electrical pulse sequence to the second anode-cathode pair. 
     
     
         11 . An electroporation ablation system for treating target tissue, the electroporation ablation system comprising:
 an ablation catheter including:
 a handle; 
 a shaft having a distal end and defining a longitudinal axis of the ablation catheter; and 
 an electroporation electrode arrangement at the distal end of the shaft and including a plurality of electrodes arranged so as to define a plurality of electrode pairs each configured to generate an electric field when an electrical pulse sequence is delivered thereto, the plurality of electrode pairs including:
 a first electrode pair arranged so as to generate a first electric field having a first orientation relative to the longitudinal axis when a first electrical pulse sequence is delivered thereto; and 
 a second electrode pair arranged so as to generate a second electric field having a second orientation relative to the longitudinal axis when a second electrical pulse sequence is delivered thereto; and 
 
   an electroporation generator operatively coupled to the electroporation electrode arrangement and configured to selectively generate and deliver the first electrical pulse sequence to first electrode pair, and the second electrical pulse sequence to the second electrode pair.   
     
     
         12 . The electroporation ablation system of  claim 11 , wherein the first orientation is generally aligned with the longitudinal axis, and wherein the second orientation is circumferential about the longitudinal axis. 
     
     
         13 . The electroporation ablation system of  claim 11 , wherein the first orientation is generally aligned with the longitudinal axis, and wherein the second orientation is transverse to the longitudinal axis. 
     
     
         14 . The electroporation ablation system of  claim 11 , wherein the first orientation is transverse to the longitudinal axis, and the second orientation is generally circumferential about the longitudinal axis. 
     
     
         15 . The electroporation ablation system of  claim 11 , wherein the first and second electrical pulse sequences each comprise a plurality of biphasic DC pulses, and the wherein the electroporation ablation generator is configured to alternate between delivering the first electrical pulse sequence to the first electrode pair, and the second electrical pulse sequence to the second electrode pair. 
     
     
         16 . A method of generating and delivering a signal to electrodes in an electroporation ablation system, the method comprising:
 delivering a first electrical pulse sequence to a first electrode pair of an electroporation catheter having a longitudinal axis so as to generate a first electric field having a first orientation relative to the longitudinal axis; and   delivering a second electrical pulse sequence to a second electrode pair of the electroporation catheter so as to generate a second electric field having a second orientation relative to the longitudinal axis.   
     
     
         17 . The method of  claim 16 , wherein delivering the first electrical pulse sequence to the first electrode pair and delivering the second electrical pulse sequence to the second electrode pair includes alternatingly delivering, over a time period, the first electrical pulse sequence to the first electrode pair and delivering the second electrical pulse sequence to the second electrode pair to produce a dynamically gyrating electric field that comprises a changing pattern over the time period. 
     
     
         18 . The method of  claim 17 , wherein the first orientation is generally aligned with the longitudinal axis, and wherein the second orientation is circumferential about the longitudinal axis. 
     
     
         19 . The method of  claim 17 , wherein the first orientation is generally aligned with the longitudinal axis, and wherein the second orientation is transverse to the longitudinal axis. 
     
     
         20 . The method of  claim 17 , wherein the first orientation is transverse to the longitudinal axis, and the second orientation is generally circumferential about the longitudinal axis.